Michael mentions that he was once told he couldn't move on to second grade, and that he "eventually aced second grade". It's often mentioned throughout the show that Michael and Phyllis are the same age/graduated the same year. If he was held back in elementary school, this would actually make him at least 1 year older than Phyllis.
When Jim suggests baskets full of cash instead of gift baskets, Andy replies "Great idea, John!" using the actor's name.
EDIT: Andy actually says "Nice work, TUNA", which is the nickname that Andy always uses to refer to Jim.
EDIT: Andy actually says "Nice work, TUNA", which is the nickname that Andy always uses to refer to Jim.
In one scene, a whiteboard is visible behind Angela. It says that Karen, who hasn't worked there for several months, has flex time; and that Ryan, who is now working at corporate, will cover the reception desk.
Michael and Dwight are arguing about the directions the GPS is giving them. As Michael turns and drives into the lake, the audio changes as if it was voiced over.